A train wreck outside of Paris tonight at the height of rush hour has shocked the nation that relies heavily on passenger rail. An intercity commuter train derailed, at least six people were killed and scores wounded.

NPR's Eleanor Beardsley has more from Paris.

ELEANOR BEARDSLEY, BYLINE: The intercity train had just left Paris on its way to Limoges when it derailed at around 5:30 p.m. local time at a station south of Paris. News channels broke into regular programming to cover the accident.

(SOUNDBITE OF NEWS BROADCAST)

BEARDSLEY: The train was not supposed to stop at the station at Bretigny-sur-Orge, and the reasons for the crash are still unknown. Analysts spoke of rails that had possibly cracked in the sudden heat wave, or couplings that could have come undone.

DOMINIQUE BUSSEREAU: (Foreign language spoken)

BEARDSLEY: Former transportation minister, Dominique Bussereau, speaking on television, said it was very unlikely that speed was a factor, as an automatic braking system would activate if the train was going too fast. The first passengers interviewed on television said the train was travelling at a normal speed when it began to shake violently.

LAURENT: (Foreign language spoken)

BEARDSLEY: We were thrown forward and smashed into the seats in front of us, says a witness named Laurent. I saw dead people and many injured. Many people were bloody and many traumatized and crying around me.

There were 370 passengers aboard the train. Other witnesses spoke of passengers being crushed or electrocuted. Television footage showed railcars crumpled against each other, with several lying on their sides, and others smashed into the station platform. Scores of fire trucks and ambulances were at the scene. An emergency plan is now in place at Paris hospitals where all non-essential surgeries have been put on hold to free up emergency facilities for train crash victims.

France has one of Europe's most extensive, efficient and safe passenger rail systems. Guillaume Pepy, head of the SNCF, the French rail service, choked up as he spoke to the media.

GUILLAUME PEPY: (Through Translator) Our first thought is one of solidarity with the victims and their families. We are all completely emotional tonight because rail accidents are something that shake us up. We are attached to trains in this country.

BEARDSLEY: French President Francois Hollande went to the scene tonight to meet with shocked passengers. As the country waits for answers, there is a pall cast over the Bastille Day weekend. Eleanor Beardsley, NPR News, Paris. Transcript provided by NPR, Copyright NPR.